1. FIELD OF THE INVENTION
The present invention relates to a method for producing a lactam having the formula: ##STR3## wherein R.sup.1 is a hydrogen atom, or a straight chain or branched chain alkyl group having from 1 to 5 carbon atoms, and R.sup.2 is an organic group having at least 2 carbon atoms, and connected at both ends to the cyclic acid imide group, which comprises reducing a cyclic acid imide having the formula: ##STR4## wherein R.sup.1 and R.sup.2 are as defined above, or its precursor, with hydrogen. More particularly, it relates to a catalyst having excellent performance for the reaction.